A ruminant animal's nutritional requirements generally are provided by forages, grains and other known feed stuffs. Pelleted feed supplements, however, are commonly used to provide nutritional fortification to the diets of ruminant animals, especially beef cattle in feedlots. These feed supplements generally have an organic component and inorganic component, each of which may form about one half, on a weight basis, of the feed supplement. The primary purpose of the feed supplement is to provide the animal with proteins, vitamins and minerals. The inorganic portion of the feed supplement frequently provides the animal with minerals and the organic portion frequently provides the animal with proteins. Ruminant animals have the capability to utilize NPN as a source of protein by virtue of bacterial conversion of NPN to protein in the stomach of the ruminant. NPN is inexpensive relative to using an organic protein source. Urea is commonly used as a source of NPN in pelleted supplements for ruminants.
When pelleted supplements containing urea are stored in vertical bins, however, it is often difficult to remove the supplements from the bin via gravitational flow. Urea-containing supplements tend to "hang-up" in the bin rather than flow freely. Precise mechanisms responsible for this problem are not well understood, but may be related to the hygroscopic nature of urea. A broad variety of measures have been used by both supplement manufacturers and supplement users to attempt to overcome this problem. These measures include minimizing steam addition during pelleting, dusting pellets with a fine, dry powder of calcium carbonate and installation of mechanical agitation equipment in the storage bins.
Ruminants such as feedlot cattle require a relatively high level of mineral supplementation in their diets. Hence, pelleted supplements tend to contain a high level of inorganic, particulate ingredients such as calcium carbonate and sodium chloride. These particulate inorganic materials constitute substantially all of the inorganic component of the feed and include mineral ingredients. Pelleted supplements also may include particulates such as urea in the organic portion of the feed. The latter mineral and urea particulates are abrasive and cause a high degree of resistance through a pelletization die. This resistance causes wear on manufacturing equipment and relatively poor production rates.
It is desirable to provide a method of increasing the efficiency and the rate production of pelletized feeds for ruminant animals, especially feeds which include a large portion of abrasive particulates such as urea and minerals such as calcium carbonate and sodium chloride.
It is desirable to provide a pelletized feed with an increased NPN content utilizing urea and a method for providing such a feed with an increased NPN content.
It also is desirable to provide a pelletized feed which includes urea and a method for improving the flowability of urea-containing pelletized feed.